Medical devices, such as balloon catheters, are used for a variety of medical procedures. Balloon catheters can be used, for example, to widen an occluded body vessel, as in angioplasty, to position an endoprosthesis, such as a stent or a graft, or to selectively block a passageway. A balloon catheter may include an inflatable and deflatable balloon positioned on a long and narrow catheter body. Initially, the balloon is folded around the catheter body to reduce the radial profile of the balloon catheter for easy insertion into the body.
During an angioplasty procedure, the folded balloon is positioned at a location in a vessel occluded by a stenosis by threading the balloon catheter through a guide catheter and over a guide wire emplaced in the vessel. The balloon is then inflated, e.g., by introducing a fluid into the interior of the balloon. Inflating the balloon can radially expand the stenosis to permit an increased rate of blood flow through the vessel. After use, the balloon is deflated and withdrawn from the body.